DRY two factor code handling in pasteboard, fix leading zero loss

WordPressAuthenticator.xcodeproj/project.pbxproj

@@ -10,6 +10,7 @@
 		020BE74A23B0BD2E007FE54C /* WordPressAuthenticatorDisplayImages.swift in Sources */ = {isa = PBXBuildFile; fileRef = 020BE74923B0BD2E007FE54C /* WordPressAuthenticatorDisplayImages.swift */; };
 		1A21EE9822832BC300C940C6 /* WordPressComOAuthClientFacade+Swift.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1A21EE9722832BC200C940C6 /* WordPressComOAuthClientFacade+Swift.swift */; };
 		1A4095182271AEFC009AA86D /* WPAuthenticator-Swift.h in Headers */ = {isa = PBXBuildFile; fileRef = 1A4095152271AEFC009AA86D /* WPAuthenticator-Swift.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		3108613125AFA4830022F75E /* PasteboardTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3108613025AFA4830022F75E /* PasteboardTests.swift */; };
 		3F550D4E23DA429B007E5897 /* AppSelectorTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3F550D4D23DA429B007E5897 /* AppSelectorTests.swift */; };
 		3F550D5123DA4A9C007E5897 /* LinkMailPresenter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3F550D5023DA4A9C007E5897 /* LinkMailPresenter.swift */; };
 		3F550D5323DA4AC6007E5897 /* URLHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3F550D5223DA4AC6007E5897 /* URLHandler.swift */; };
@@ -213,6 +214,7 @@
 		1A21EE9722832BC200C940C6 /* WordPressComOAuthClientFacade+Swift.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "WordPressComOAuthClientFacade+Swift.swift"; sourceTree = "<group>"; };
 		1A4095152271AEFC009AA86D /* WPAuthenticator-Swift.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "WPAuthenticator-Swift.h"; sourceTree = "<group>"; };
 		276354F054C34AD36CA32AB6 /* Pods-WordPressAuthenticator.release-alpha.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-WordPressAuthenticator.release-alpha.xcconfig"; path = "Pods/Target Support Files/Pods-WordPressAuthenticator/Pods-WordPressAuthenticator.release-alpha.xcconfig"; sourceTree = "<group>"; };
+		3108613025AFA4830022F75E /* PasteboardTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PasteboardTests.swift; sourceTree = "<group>"; };
 		33FEF45B466FF8EAAE5F3923 /* Pods-WordPressAuthenticator.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-WordPressAuthenticator.release.xcconfig"; path = "Pods/Target Support Files/Pods-WordPressAuthenticator/Pods-WordPressAuthenticator.release.xcconfig"; sourceTree = "<group>"; };
 		37AFD4EF492B00CA7AEC11A3 /* Pods-WordPressAuthenticatorTests.release-alpha.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-WordPressAuthenticatorTests.release-alpha.xcconfig"; path = "Pods/Target Support Files/Pods-WordPressAuthenticatorTests/Pods-WordPressAuthenticatorTests.release-alpha.xcconfig"; sourceTree = "<group>"; };
 		3F550D4D23DA429B007E5897 /* AppSelectorTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppSelectorTests.swift; sourceTree = "<group>"; };
@@ -535,6 +537,7 @@
 		B501C03D208FC52500D1E58F /* Authenticator */ = {
 			isa = PBXGroup;
 			children = (
+				3108613025AFA4830022F75E /* PasteboardTests.swift */,
 				B501C03E208FC52500D1E58F /* WordPressAuthenticatorTests.swift */,
 				CE16177721B70C1A00B82A47 /* WordPressAuthenticatorDisplayTextTests.swift */,
 				BA53D64724DFDF97001F1ABF /* WordPressSourceTagTests.swift */,
@@ -1362,6 +1365,7 @@
 				BA53D64B24DFE07D001F1ABF /* WordpressAuthenticatorProvider.swift in Sources */,
 				CE16177821B70C1A00B82A47 /* WordPressAuthenticatorDisplayTextTests.swift in Sources */,
 				B501C048208FC79C00D1E58F /* LoginFacadeTests.m in Sources */,
+				3108613125AFA4830022F75E /* PasteboardTests.swift in Sources */,
 				D85C36F0256E118D00D56E34 /* NavigationToEnterAccountTests.swift in Sources */,
 				D85C36E6256E0DDE00D56E34 /* NavigationToEnterSiteTests.swift in Sources */,
 				D85C3882256E3FEC00D56E34 /* WordPressComSiteInfoTests.swift in Sources */,

WordPressAuthenticator/Extensions/UIPasteboard+Detect.swift

@@ -25,4 +25,53 @@ extension UIPasteboard {
             }
         }
     }
+
+    /// Attempts to detect and return a authenticator code from the pasteboard.
+    /// Expects to run on main thread.
+    /// - Parameters:
+    ///   - completion: Called with a length digit authentication code on success
+    @available(iOS 14.0, *)
+    public func detectAuthenticatorCode(length: Int = 6, completion: @escaping (Result<String, Error>) -> Void) {
+        UIPasteboard.general.detect(patterns: [.number]) { result in
+            switch result {
+                case .success(let detections):
+                    guard let firstMatch = detections.first else {
+                        completion(.success(""))
+                        return
+                    }
+                    guard let matchedNumber = firstMatch.value as? NSNumber else {
+                        completion(.success(""))
+                        return
+                    }
+
+                    let authenticationCode = matchedNumber.stringValue
+
+                    /// Reject numbers with decimal points or signs in them
+                    let codeCharacterSet = CharacterSet(charactersIn: authenticationCode)
+                    if !codeCharacterSet.isSubset(of: CharacterSet.decimalDigits) {
+                        completion(.success(""))
+                        return
+                    }
+
+                    /// We need length digits. No more, no less.
+                    if authenticationCode.count > length {
+                        completion(.success(""))
+                        return
+                    } else if authenticationCode.count == length {
+                        completion(.success(authenticationCode))
+                        return
+                    }
+
+                    let missingDigits = 6 - authenticationCode.count
+                    let paddingZeros = String(repeating: "0", count: missingDigits)
+                    let paddedAuthenticationCode = paddingZeros + authenticationCode
+
+                    completion(.success(paddedAuthenticationCode))
+                    return
+                case .failure(let error):
+                    completion(.failure(error))
+                    return
+            }
+        }
+    }
 }

WordPressAuthenticator/Signin/Login2FAViewController.swift

@@ -296,14 +296,12 @@ class Login2FAViewController: LoginViewController, NUXKeyboardResponder, UITextF
         }
 
         if #available(iOS 14.0, *) {
-            UIPasteboard.general.detect(patterns: [.number]) { [weak self] result in
+            UIPasteboard.general.detectAuthenticatorCode() { [weak self] result in
                 switch result {
-                case .success(let detections):
-                    if let pasteString = detections.first?.value as? String {
-                        self?.handle(code: pasteString)
-                    }
-                case .failure:
-                    break
+                    case .success(let authenticatorCode):
+                        self?.handle(code: authenticatorCode)
+                    case .failure:
+                        break
                 }
             }
         } else {

WordPressAuthenticator/Unified Auth/View Related/2FA/TwoFAViewController.swift

@@ -318,13 +318,10 @@ private extension TwoFAViewController {
         }
 
         if #available(iOS 14.0, *) {
-            UIPasteboard.general.detect(patterns: [.number]) { [weak self] result in
+            UIPasteboard.general.detectAuthenticatorCode() { [weak self] result in
                 switch result {
-                    case .success(let detections):
-                        if let pasteCode = detections.first?.value as? Int {
-                            let pasteString = String(pasteCode)
-                            self?.handle(code: pasteString, textField: codeField)
-                        }
+                    case .success(let authenticatorCode):
+                        self?.handle(code: authenticatorCode, textField: codeField)
                     case .failure:
                         break
                 }

WordPressAuthenticatorTests/Authenticator/PasteboardTests.swift

@@ -0,0 +1,54 @@
+import XCTest
+
+class PasteboardTests: XCTestCase {
+    let timeout = TimeInterval(3)
+
+    override class func tearDown() {
+        super.tearDown()
+        let pasteboard = UIPasteboard.general
+        pasteboard.string = ""
+    }
+
+    func testNominalAuthCode() throws {
+        guard #available(iOS 14.0, *) else {
+            throw XCTSkip("Unsupported iOS version")
+        }
+
+        let expect = expectation(description: "Could read nominal auth code from pasteboard")
+        let pasteboard = UIPasteboard.general
+        pasteboard.string = "123456"
+
+        UIPasteboard.general.detectAuthenticatorCode() { result in
+            switch result {
+                case .success(let authenticationCode):
+                    XCTAssertEqual(authenticationCode, "123456")
+                case .failure(_):
+                    XCTAssert(false)
+            }
+            expect.fulfill()
+        }
+
+        waitForExpectations(timeout: timeout, handler: nil)
+    }
+
+    func testLeadingZeroInAuthCodePreserved() throws {
+        guard #available(iOS 14.0, *) else {
+            throw XCTSkip("Unsupported iOS version")
+        }
+
+        let expect = expectation(description: "Could read leading zero auth code from pasteboard")
+        let pasteboard = UIPasteboard.general
+        pasteboard.string = "012345"
+
+        UIPasteboard.general.detectAuthenticatorCode() { result in
+            switch result {
+                case .success(let authenticationCode):
+                    XCTAssertEqual(authenticationCode, "012345")
+                case .failure(_):
+                    XCTAssert(false)
+            }
+            expect.fulfill()
+        }
+
+        waitForExpectations(timeout: timeout, handler: nil)
+    }}